The GT6’s nuclear industry is coming,will nuclear fuels only be used to make fuel rods to generate electricity? We probably can added some nuclear weapon which can provide more usages for radiation materials.(I know some people probably do not like nuclear weapons,I am sorry)

By the way, when I use uranium dust to get U235 and Pu241,where is my U238 left?

Yes GT6 will have Nuclear Reactors
No, I will probably not add Nukes, there is other compatible Mods for that, like ICBM and IC2.
The Remaining U238 was deleted for balance Reasons, otherwise you could just feed it back in like with the Kovarex Process in Factorio.